It's hard to understand what is going on with them and not it will become interesting. They extended Guardiola's contract and it would be ridiculous if they sack him weeks later, so I suppose they are going on with him no matter what's going to happen.
Sacking him after extending his contract weeks ago will really be ridiculous and will be the loss of the club because finding a good coach nowadays is not easy, we have seen how Chelsea and Manchester United were struggling to have a decent coach so sticking with him the best option for them.
Sacking Guardiola will be a poor decision because this is only the first time his team has struggled this much so if the team doesn't trust him in a time like this, it means they don't deserve him. As you said, it's difficult to explain what is really wrong with them, but we have to remember that Rodri was not the only player he missed. He was without KDB, Doku, Grelish, Ake, Dias, and Stones at a certain point in this season.
I believe with a few players in strategic positions Pep can get his team back to winning ways. Players like Walker and Gundugan have failed to live up to expectation so people shouldn't regard them as top players. KDB has been too injury prone to be at top level. Worst of all, Pep's system relies on a DM and without a reliable DM they'll struggle.
Sacking him is not the best thing because seeing a manager as good as him will be difficult so they should be patient with him until he figures out what is wrong and find a solution. I don’t think players are the problem, he is not the only team that suffered injuries and he should know that injuries will certainly occur and should be prepared for it, in the past seasons his players suffered injuries and still was able to manage the available ones so i don’t think it’s the injuries. He needs to recruit more players especially wingers because Doku and Savinho are not up to standards and haven’t been contributing enough. We will see what will happen if Rodri joins the team back.